Just like there are roads on the ground for ground vehicles to travel on, the sky is filled with highways in the air, called airways, for aircraft to travel through.

An airway, or air route, is a defined corridor that connects one specified location to another, at a specified altitude, along which an aircraft that meets the requirements of the airway may be flown. Airways are defined with segments within a specific altitude block, corridor width, and between fixed geographic coordinates for satellite navigation systems, or between ground-based radio transmitter navigational aids (navaids) (such as VORs or NDBs), or the intersection of specific radials of two navaids.